LABEL-FREE CELL COUNTING VIA DAA

This is a schematic of the pinwheel effect induced by lysed cells. (A) GdnHCl lyses the cells and drives the released DNA to adsorb on to silica-coated paramagnetic beads, which form aggregates in a rotating magnetic field (RMF). Images of the aggregation are digitized, from which the initial concentration of cells can be measured. (B) Shown are photographs of the same amount of beads with different amounts of DNA that are equivalent to 0, 2, 8, and 32 cells, respectively. Magnetic beads, which remain dispersed in RMF, form visually detectable aggregates within minutes upon mixture with lysed human cells.

ENUMERATING CD4+ T CELLS VIA DAA FOR DIAGNOSIS OF AIDS

Quantification of CD4+ T cells. The pinwheel result correlates well with flow cytometry when the post-drawn time of blood is less than 24 h, as shown in (A) and (B). For the samples with post-drawn time over 24 h, the accuracy of the pinwheel assay is compromised due to the deterioration of sample quality, as shown in (C) and (D). The solid blue lines in (B) and (D) represent linear calibration functions, and the black dashed lines show y = x. The gray dashed lines represent the threshold (350 cells per μL) that defines the starting time of ARV for HIV patients (for (B), R2 = 0.997; for (D), R2 = 0.775). The arrows in (C) and (D) point to the only sample that generated a false result in the pinwheel assay.